Socio-economic status (SES) produces wide disparities in health. These disparities are a problem because they describe increased risk for chronic diseases and early death for lower SES individuals and large costs to the U.S. economy due to health care and lost productivity. The long-term goal is to better understand the pathways by which lower SES results in worse health. The overall objective in this R03 is to test chronic stress as an explanation of SES-related health disparities. In contrast to previous daily stress studies, this R03 uses data from an economically and racially diverse sample of adults and has fine-grained data regarding the timing of stressors. The central hypothesis, drawn from several health disparity theories, is that lower SES individuals experience persistent exposure and prolonged response to stressors and that this frequent and extended activation of emotional responses results in physical wear-and-tear and eventual disease. The rationale for the proposed research is that by understanding the pathways by which SES-related stress reduces physical health, interventions can be developed to reduce physical symptoms on a daily basis and delay or prevent disease over the long-term. Guided by preliminary work, this chronic stress hypothesis will be tested on short- and long-time scales. Specific aims extended from this hypothesis include: 1) Test the prediction that, over the short-term, low SES will be associated with more frequent daily stressors and emotional responses to stressors which are larger in magnitude and duration, 2) Test the prediction that, on a daily basis, having emotional responses to daily stressors which are larger magnitude and longer duration predicts experiencing more frequent and severe physical symptoms on a daily basis, and 3) Test the prediction that, over a lifetime, low SES in childhood predicts worse physical health in adulthood because of more exposure to stressors and reduced psychosocial resources with which to respond to them. Under the first aim, magnitude of emotional reactivity will be distinguished from duration of emotional recovery - which the applicant has demonstrated is feasible in her preliminary work. Under the second aim, these magnitude and duration slopes of emotional responses to stressors across the day will be used to predict end of day physical symptoms. In the third aim, childhood and lifetime stress will be tested as mediators of the effects of objectiv indices of childhood SES on adult health. The approach is innovative, in the applicant's opinion, because it tests theory-based predictions for health disparities, leverages a diverse sample, and approaches the predictions at multiple time scales. The proposed research is significant because it is expected to advance and expand understanding of how SES disadvantage results in wide disparities in health. Such knowledge has the potential to direct interventions to the chronic stress pathways most predictive of daily and long-term health.